The present invention generally relates to electrical ground flow interrupters. More specifically, this invention relates to twist-on wire connectors of the type widely known in the electrical equipment industry as "wire nuts".
Twist-on wire connectors comprising a hollow plastic shell with a coiled metal spring threadedly attached to the inside surface of the shell are generally known and widely used in the prior art. Twist-on connectors are used to connect two or more wires on the same electrical circuit to either branch off voltage to other locations or to continue the circuit in a junction box. Prior to this invention, no twist-on wire connectors having visual means to indicate voltage across connected wires is disclosed. The prior art also does not disclose the use of lighted wire connectors for visual troubleshooting of electrical circuits.
Visual indicators of the presence or level of voltage in an electrical conductor are known in the prior art. For example, U.S. Pat. No. 4,152,643 to Schweitzer, Jr. discloses a test point cap that selectively mounts to the test point terminal of a cable connector and emits a flashing light in response to the connector being energized by a high voltage alternating current. U.S. Pat. No. 3,328,690 to Lockie et al discloses a glow tube ionized by an electric field to visually indicate voltage in shielded cable. U.S. Pat. No. 4,171,523 to Parkitny discloses a lamp voltage indicator for electric fences. In U.S. Pat. No. 3,343,153 to Waehner there is shown a separable connector for a high voltage electrical power cable having a glow lamp selectively operable to indicate the presence of a voltage drop across the connector.
Other less closely-related visual voltage indicators are shown in the following prior art patents. U.S. Pat. No. 1,913,155 to Ferguson discloses an improved rarefied gas-filled tube for use as an electric potential indicator. U.S. Pat. No. 3,471,784 to Arndt et al discloses a magnetic loop around a conductor within its insulation constituting part of a capacitive voltage divider/voltage pickup for powering a voltage monitor. U.S. Pat. No. 3,513,394 to Tachick discloses an insulated high voltage source for high voltage conductor terminations having a capacitive voltage divider adapted to energize voltage indicating means. In U.S. Pat. No. 3,524,178 to Stratton improvements in a capacitance tap and lamp to indicate voltage in a power cable or cable termination housing are disclosed. U.S. Pat. No. 4,259,545 to Hayden discloses a glow lamp or fluorescent indicator connected to the insulator of an electrical power line.
Lighted twist-on wire connectors provide distinct advantages over the twist-on connectors of the prior art. A particular advantage is the use of lighted twist-on connectors to reduce the time and equipment needed for electrical circuit troubleshooting operations. In the present art troubleshooting operations require the use of voltage meters and other tools to determine if there is a voltage drop across connected wires. A lighted twist-on connector made operable by a voltage across the ends of connected wires permits visual troubleshooting. The absence of voltage in a wire can thus be more quickly isolated to speed up troubleshooting operations.
Lighted twist-on connectors are also useful to monitor machine components, for example the starter. By having a visual indicator of voltage to indicate when the starter is energized, the machine can be operated more safely. Lighted twist-on connectors also permit visual checks on various parts of an engine, electrical assembly and the like.
Therefore, it should be understood from the foregoing that there exists a need in the art for a lighted twist-on wire connector.